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Forgot to take one med
Oct 27, 2004

I am on tenofovir, 3TC, nevirapine. Have been on treatment for 4 years. Solid results throughout. At last test 1300 CDs, <50 VL, 44%. Recently I mixed up my pills and realised after 5 days that I had been taking a double dose of 3TC with nevirapine but had missed tenofivir for 5 days. How likely/unlikely is it that resistance would have developed? I am thinking the likelihood is low as two drugs were in the system throughout. Do I need a sooner than scheduled blood test?

Thanks for your assistance.

Response from Dr. Sherer

I would agree with you that the likelihood of viral breakthrough and resistance on the basis of this error is small. I would discuss this with your physician regarding whether an earlier viral load test is warranted; my opinion would be that it is not.

One reason is that after full suppression on ART, when the ART is stopped, viral replication is not detectable in the blood for 7 days.

Another is that tenofovir has a long plasma half life, so you had therapeutic levels for 1-2 days after your first missed dose, and you had two other active drugs in your blood during all five days.

As above, I urge you to inform your physician of this error and decide with him or her what the next steps should be.

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